Separator feeding means



1961 M. L. E. VAN TITTELBOOM 2,995,245

SEPARATOR FEEDING MEANS Filed March 17, 1959 1N VENTOR. JYQTCQZZLEzlan/jziileoom BY MW United States Patent 2,995,245 SEPARATOR FEEDINGMEANS Marcel L. E. van Tittelboom, Sas van Gent, Netherlands, assignorto Corn Products Company, a corporation of Delaware Filed May 17, 1959,Ser. No. 799,902 Claims priority, application Netherlands Apr. 11, 19584 Claims. (Cl. 209-254) The present invention relates to separators, andmore particularly to means for feeding a suspension or slurry onto ascreen. The separator feeding means herein disclosed as an embodiment ofthe invention is utilized for feeding a screen for separating starchfrom fibrous material when both are contained or conveyed in a slurry orwater suspension. While this is the preferred application of theinvention, separation of other materials may be carried out by means ofthe invention, the true scope of which is to be ascertained from theappended claims.

In the recovery of starch from vegetable material con taining starchgranules, for instance, soaked corn, from which the germs have beenremoved, a slurry or other suspension containing starch granules andfibers is obtained by grinding the vegetable product, from which slurrythe starch granules are washed out on screens. These screens may be ofvarious constructions. According to the classical method fiat Shakingsieves are used, but of late years also screening apparatus with curvedscreening surfaces along which the slurry is propelled under pressurehave been suggested. In those screening apparatuses, the slurrycontaining the starch granules and fibers is supplied to the screensthrough a supply slot intended to produce a uniform spreading of theslurry over the entire width of the screen. In practice, the difficultynow appears that the supply slot supplied from the side or sides isclogged up by fibrous material owing to which the screening process mustbe interrupted rather often to clean the supply slot of the screen.

It has now been found that this drawback can be substantially completelyovercome by having the upper side of the supply slot consist of thelower side of a pivoted or swinging control valve, exerting a backpressure on the slurry supplied.

Such a control valve not only is important in a supply slot for screenson which fibrous material is washed out, but in general, in conduitsthrough which suspensions of fibrous material are transported and whichare provided with a narrowed passage opening. Here also trouble isencountered in that the passage opening becomes clogged up from thewalls of the conduit, for instance at the location of a valve.Surprisingly, it has appeared that when applying a control valveexerting a back pressure on the suspension transported substantially nodeposits of fibrous material occur.

The invention provides a method of transporting suspensions of fibrousmaterial through a conduit having a narrowed passage opening in whichthe narrowed passage opening is provided with a freely pivoted controlvalve exerting a back pressure on the flow of fibrous material, themagnitude of the back pressure being adjustable, if desired.

The magnitude of the back pressure exerted may be adjusted in variousmanners, e.g., with the aid of an adjustable spring connected with thecontrol valve. According to the invention, however, preferably use ismade of a control valve which is freely pivoted through its mounting ona rockable shaft provided with a lever with an adjustable counterweight.Such adjustable spring or counterweight constitutes adjustable loadingmeans for the valve.

The invention further includes the combination of such back pressureretaining means with a screening apparatus to which the material to bescreened can be uniformly supplied via a supply slot the upper side ofwhich consists of the lower side of a freely pivoted control valve. Herealso the back pressure exerted by the control valve, if desired, can bevaried by various means, but preferably a control valve is used which isarranged on a rockable shaft provided with a lever with an adjustablecounterweight.

A further and additional feature of the invention involves the use ofmeans for distribution of flow lengthwise of the slot. This may be doneby the use of a supply conduit disposed generally lengthwise of the slotopening laterally into the slot. Since this in effect forms an elbowwith a tendency for uneven flow along the length of the slot, a seriesof guide blades may be employed to distribute the fiow along the lengthof the slot.

Now in order to acquaint those skilled in the art how to make and use myinvention, I shall describe a specific embodiment of the same inconjunction with the accompanying drawings in which:

FIGURE 1 is a vertical section along the line 1-1 in FIGURE 2 of thatpart of the screening apparatus according to the invention where thesuspension of fibrous material to be screened is supplied to the screen;

FIGURE 2 is a horizontal section along the line 22 in FIGURE 1 of thatpart of the screening apparatus ac cording to the invention.

In the supply according to FIGURES 1 and 2, the sus pension of fibrousmaterial is supplied through conduit 1. Via the stationarily arrangedguide blades 2, 3 and 4, which control distribution lengthwise of theslot, the material arrives in the supply slot 5 of screen 6 which may beeither flat or curved, and which comprises a bottom wall of sheet screenand imperforate side walls. The upper side of the supply slot is formedby the lower side of the control valve 7. This control valve is pivotedbecause it is mounted on the rotatable or rockable shaft 8 which isprovided with a lever 11 with a counterweight 12. The shaft 8 reposes ina prolongation 9 of the casing connected to the conduit by bolts 10,said prolongation 9 of the casing constitutes a nozzle member directingthe fiow of slurry substantially tangentially onto the screen 6.

Besides that it prevents the clogging up of the supply slot, the controlvalve has the advantage that when, for instance, foreign matter, such aspieces of corn cob, or pieces of stone, are present in the materialsupplied, it can turn upward to let them through. Furthermore, it willautomatically leave a larger passage for a greater volume of liquiddelivered by the supply pump, the back pressure exerted by the valve 7upon the flow of liquid remaining substantially constant.

The invention provides the dual function of maintaining a substantiallyuniform back pressure, the valve 7 being suitably curved substantiallyin the form of an involute, and of rising to pass objects, such aspieces of corn cob or stones, which are carried by the current of fluidto prevent their lodging and forming stationary obstructions.

The device may be used with any desired supply means.

It is useful in conjunction with the delivery of a centrifugal pump orthe like which has the characteristic of decrease of pressure withincreasing volume of delivery and vice versa. It is useful also tocompensate for variations of delivery pressure from Whatever cause bytending to keep the back pressure approximately uniform, and hence thedelivery velocity approximately uniform.

The device above disclosed is particularly useful in the separation ofstarch from fibers in the wet milling of corn (maize). In that service,the starch-fiber slurry is delivered by a centrifugal pump (not shown)through a delivery pipe connected to conduit 1. The flow of slurry whichoccurs longitudinally of the conduit 1 is to be delivered atsubstantially uniform depth and substantially the same rate of flow overthe full width of the screen 6. The total flow may obviously be greateror less. The fiow of slurry is to be conducted longitudinally of thescreen. Hence, in the structure shown in the drawings, the flowingstream of slurry is required to change its direction of flow from thatindicated by the arrow in FIG- URE 2 to a direction at right anglesthereto. At the same time, the flow is to be distributed substantiallyevenly along the length of the slot or opening 5 which is served by thevalve 7. The vanes 2, 3 and 4 assist in distribution of the flowlongitudinally of the slot and in bringing about the change in directionof the flow above referred to.

The pressure of the slurry against the valve 7 will tend to swing it ina clockwise direction as viewed in FIGURE 1 against the loading of theweighted lever 11. The yieldable resistance of the weighted lever uponthe valve tends to maintain a back pressure which serves to equalize theflow of slurry along the length of the slot or opening. There must be adifference in pressure upon its opposite sides for it to move in thedirection to widen the slot opening. A predetermined back pressure isexerted by the said weighted lever for various degrees of opening of thevalve. In the event of a tendency to lodge a deposit of fibers or othernon-fluid matter at this point, the difference in pressure exerted onopposite sides of the valve 7 will tend to force the material throughthe opening of the slot, thereby moving the valve 7 farther towards openposition and thus permitting passage of the blocking material.

I claim:

1. In a device of the class described having a longitudinally extendingscreen having imperforate sidewalls and a bottom stationary screen wall,the improvement which comprises a nozzle member having an inlet and anoutlet, the outlet being in the form of a narrow nozzle outlet the lowerwall of which is substantially flush with the screen wall, and the upperwall of which is adjustable to vary the vertical size of the outletopening, a valve pivoted along one transverse edge in the nozzle memberthe other being movable to vary the size of said nozzle opening, loadingmeans for said valve tending to move the movable edge of the valvetowards the lower wall of the nozzle opening, and a supply connectionfor said nozzle member.

2. In combination, a stationary screen having imperforate side wallsextending longitudinally of the screen for guiding a flow of slurrylongitudinally of the screen, a closed conduit for delivering a streamof slurry of starch and fibrous material onto said screen in a directionlongitudinally of the screen, said conduit being disposed with itslongitudinal axis lying transversely of the screen and extending forapproximately the full width of said screen between said side walls,said conduit having a slot extending lengthwise of the conduit andsubstantially parallel of the surface of the screen, the bottom of saidslot lying substantially level with the surface of the screen wherebythe stream of slurry is directed onto the screen substantiallytangentially thereof, a flap valve hinged at its upper edge along theupper edge of the slot and opening towards the screen, and means foradjustably loading the flap valve to bias it towards closed position,said flap valve affording a yieldable resistance to the fiow of slurrythrough said slot and onto the screen whereby a back pressure isproduced behind the valve.

3. The combination of claim 2 with flow directing vanes disposed in saidslot transversely of the longitudinal axis of the conduit.

4. In a starch separator having a longitudinally extending stationaryscreen having imperforate side walls and a bottom screen wall, theimprovement which comprises a nozzle member having a narrow dischargeopening extending substantially for the full width of the screen fordischarging a slurry of starch and fibre longitudinally of the screensubstantially tangential to said bottom wall of said screen, ahorizontally disposed rockable shaft pivoted in said nozzle memberadjacent the upper edge of said opening and having a weighted leverexternally of said member, a valve connected at its rear end to saidrockable shaft and having its front end forming the upper wall of saidnozzle for defining a narrow but adjustable slot extending substantiallythe full width of said nozzle member, a supply connection for saidnozzle member comprising a laterally extending stationary tubularfitting having an oblong outlet opening along its side communicatingwith the rear end of said nozzle member, said weighted lever tending toturn said shaft in valve closing direction, and a plurality of fiowdividing guide blades in said oblong outlet opening to distribute theflow of slurry lengthwise of said valve.

References Cited in the file of this patent UNITED STATES PATENTS750,092 Cornwall Jan. 19, 1904 987,657 Wagner Mar. 21, 1911 FOREIGNPATENTS 293,418 Switzerland Dec. 16, 1953 v UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent N0. 2,,995,245- August 8 1961 Marcel LoE van Tittelboom It is hereby certified that error appears in the abovenumbered pat-'- ent requiring correction and that the said LettersPatent should read as corrected below.

Column 3 line 42, after "other" insert edge Signed and sealed this 12thday of December 1961.;

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Commissioner of Patents Attesting OfficerUSCOMM-DC UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo. 2,995,245 r August 8V I961 Marcel L. E, van Tittelboom It is herebycertified that error appears in the above numbered pat-'- ent requiringcorrection and that the said Letters Patent should read as correctedbelow.

Column 3 line 42 after "other" insert edge Signed and sealed this 12thday of December 1961;

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of PatentsUSCOMM-DC

